Multiplayer first person shooter games for Xbox 360 with 6-player support
Quake II
Players: 4 local, 0 online
Call of Duty: Black Ops
Players: 2 local, 6 online
Duke Nukem 3D
Players: 0 local, 8 online
Brink
Players: 0 local, 8 online
Marathon: Durandal
Players: 4 local, 8 online
Call of Duty: Ghosts
Players: 2 local, 6 online
America's Army: True Soldiers
Players: 2 local, 16 online